1. Field of the Invention
The present invention relates to an image sensor, an imaging system, a sensor, and an operation method for the image sensor.
2. Description of the Related Art
In an image sensor, a row selecting circuit selects a row of a pixel array, and a plurality of pixels on the selected row output signals to a plurality of column signal lines. A column selecting circuit then outputs signals from the pixels on one row while sequentially selecting a plurality of column signal lines. The image sensor sequentially performs this operation for a plurality of rows while changing a row to be selected. In a conventional image sensor, a readout period for signals is constant regardless of any row selected from a plurality of rows of a pixel array.
However, in an image sensor including a pixel array and a horizontal output circuit which sequentially selects and outputs signals output from the pixel array to a plurality of column signal lines, a shortage of readout period can occur more with an increase in distance from the horizontal output circuit. Such a problem becomes more conspicuous in an image sensor with a large pixel array size of several tens of cm. Shortages of readout period corresponding to row positions can cause shading.